Valve mechanism



Patented Jan. 3, 1950 VALVE MECHANISM Roger H. Casler, Oakville, Conn., assignor to Bendix-Westinghouse Automotive Air Brake Company, Elyria, Oh

ware

io, a corporation of Dela- Application September 18, 1946, Serial No. 697,755

13 Claims.

This invention relates to fluid pressure control mechanism, and more particularly to valve mechanism for controlling the supply of fluid pressure to the actuators of such a system.

It has previously been proposed to provide valve mechanisms of the self-lapping type for accurately controlling the pressure of fluid supplied to the actuators of a fluid pressure control system, but many of these valve mechanisms have required the use of relatively large pressure responsive members for controlling the operation of the valves in the valve mechanism, with the result that the valve mechanism has been relatively large, and with the further result that the operator has been required to exert an unduly large force on the operating element in order to control the action of the valve mechanism. It is accordingly an object of the present invention to provide valve mechanism of the self-lapping type so constituted as to eliminate the use of relatively large pressure responsive control members, and at the same time to materially reduce the over-all size of the valve mechanism.

Another object of the invention is to provide,

in control valve mechanisms of the above type, I 1

means for controlling the operation of the valves, so constituted as to minimize or materially reduce the force required to operate the valve mechanism.

A further object of the invention is to provide means for balancing or partially balancing the valves of the mechanism, in order to reduce the force required to control the mechanism.

Still another object of the invention is to provide simple and eflicient self-lapping control valve mechanism, so constituted as to accurately control the supply of fluid pressure to the actuators of a fluid pressure control system.

Another object of the invention is to provide means for permitting alignment of the valves 1 with their respective seats in order to minimize leakage when the valves are closed.

Other objects and features of novelty will appear more fully from the following detailed description when taken in connection with the ac- 1 several views:

'a fluid pressure control system having a control valve mechanism of the above type, and

Fig. 2 is a view, partially in section, of a fluid pressure control system provided with a modifled form of valve mechanism.

Referring to Fig. 1 of the drawings, a fluid pressure control system is shown as comprising a reservoir 4 adapted to receive a fluid pressure from a compressor, not shown, through a conduit 5, a self-lapping control valve mechanism 6 adapted to receive fluid pressure from the reservoir through a conduit 1, a pair of fluid actuators 8 adapted to receive fluid pressure from the control valve mechanism through conduits 9 and i0, and a pair of operating levers ll adapted to be actuated through rods [2.

As shown in the drawing, the valve mechanism 6 is provided with a casing l3 having an inlet chamber I4 connected with the conduit 1, an outlet chamber l5 having a chamber [6 connected thereto at all times by means of a passage |1 formed in the casing, and an exhaust chamber l8 having an atmospheric or exhaust port l9. A bore 20, preferably of uniform cross section, is formed in the casing as shown, and serves to connect all of the above referred to chambers. A valve operating element 2| is slidably mounted in the bore as shown, and is connected at its lower end with a spherical inlet valve 22 by means of a stem 23 connected to the lower end of the element 2| by means of a ball and socket joint 24, the construction of the joint being such that the valve moves with the valve operating element axially, but is free to move laterally in order to permit the ball to seat properly on the lower end of the bore 20. The inlet valve and valve operating element are normally 'maintained in the position shown by means of an inlet valve spring 25 interposed between the casing and the inlet valve. Since the chamber I 6 is connected with the outlet chamber l5 by means of the passage IT, a seal 26 is provided in the bore 20 directly above the chamber I 6 in order to prevent leakage from the chamber [6 to the exhaust chamber l8 by the valve operating element 2|. The upper end of the valve operating element is provided with a bore 21 connected with the chamber I6 by means of ports 28, and connected at its upper end with an enlarged bore 29 which is preferably of substantially the same diameter as the bore 20. A valve operating plunger 30 is slidably mounted in a bore 3| formed in the upper portion of the casing, the outer periphery of the plunger being provided with notches 32 in order to permit unrestricted flow of fluid pressure from the lower portion of the exhaust chamber to the upper portion, and thence to the exhaust port l9. The plunger is provided with an upwardly extending stem 33 guided at its upper end in a bore 34 formed in a washer 35 slidably mounted in the upper portion of the bore'3I, and adapted to be moved downwardly by means of a control lever 36 having an operative connection therewith through the medium of a plunger 31 slidably mounted in a bore 38 formed in a cover-plate 39 attached to the upper portion of the housing by means of suitable cap screws "40. A graduatlng spring 4! is interposed between the washer 35 and the plunger 30, and it will be understood that on downward movement of the lever 36, which is pivotally connected with *thebasi'ngby means of a pivot pin 42, the graduating spring will be compressed, and a spherical exhaust valve 43, mounted on a stem 44, extending downwardly from the plunger 3Il,will be forced against the upper end of the bore 29 in order to prevent communication between the outlet chamber I5 and the exhaust chamber I8 "throughtp'assag'e :I'I, chamber 15, ports 28, and'bores 21 and In order to permit alignment of the exhaust valve with its seat, theplunger 30 is loosely fitted in the bore 3 I.

Asheretofore stated, the diameter of the bore i is preferably uniform, and it will therefore be understood that the efiective area of the inlet valve 2 2 is substantially identical with the area of the valve operating element which is subjected at its upper end to the pressure in the chamber I 6. Thus with the parts in the position shown,

the force exerted by the' fluid pressure'in the inlet chamber It to move theinlet valve toward open position is identical with the force exerted on theelement -2I in the opposite direction-tornaintain the inlet valve in closed position. These forces are therefore balanced when there -is no pressure in =the outlet chamber, and the inlet valve is maintained in closed position by the 'force exerted-by the spring-25. In this particular embodimentof the-invention, the exhaust valve 43 may'be normally maintained in closedaposition by'gravity with a relatively small force,-and on counterclockwise movement of the control lever 66, the'graduating spring 4| will be'compressed, and-the valve operating element will be moved downward-to open'the inlet valvein order-to connect the inlet chamber I4 with the outlet cham- -ber-I5, and-with the chamber I5 through the-port I1. 'Sincethe upper end of the bore-29is closed by theexhaust valve under this condition of operation, the valve operating element 21 will act as a piston, and-the pressure difierential between chambers I4 and I6 and between chambers I-6 and I8, will tend to force the element upward =against the'force exerted by the graduating spring 4| to close the inlet valve. At the sametima the pressure differential between chambers I4 and I5 will tend'to force the spherical inlet valve 22 toward closed-position as the pressure in chamber I5 increases. As the pressure increases in the "chamber I6, the' upward force on the element will correspondingly increase, and the inlet valve will be'closed when the pressure in the passage I1 and in-the chamber I6 reaches a predetermined value dependent'on the degree 'of downward force exerted by the graduating spring. In the event the-pressure in the chamber I6 increases beyond -a predetermined value, due to leakageof th'e inlt valve, the valve 43 will'be moved upward from its seat in i order to discharge the excess-pressure to atmosphere through the exhaust port I9. On release movement of the control pedal in a clockwise direction, the tension of the graduating spring will be decreased, and the pressure acting on the lower end of the exhaust valve in the bore 29 will move the valve away from-its seat in order to permit the exhaust of fluid pressure from the chamber I5 through passage I2, chamber I 6, ports 28, bore 21, bore 29, exhaust chamber I8 and exhaust port I9, the degree of fluid pressure released in this manner being dependent on the degree of release movement of the control pedal. On complete :r-elease of the control edal, the pressure acting on the lower end of the exhaust valve need only overcome the weight of the parts associated therewith, and consequently the pressure in chamber IE will be substantially reduced to atmospheric pressure.

It will be apparent from the foregoing, that a fiuid pressure control valve of the self-lapping type -'has been provided, wherein the-forcesrequlred --to operate the control pedal are I relatively small, due to the balancing of the'inlet valve by the "element -2I acting as "a piston, 'and wherein 'the :pressuredelivered to the actuators-is at all times-substantially proportional to'the degree of movement'of the controlpedal from release positionas well as to the forceexerted by the controlrpedal'on theplunger 3Ito' compress the graduating spring Referring now to Fig. 2- of the drawings, whereing a similarcontrol valve of modified form 'is :ill-ustratedya'c'asing 45 is provided with aninlet chamber '43, an outlet chamber 47, and :an exhaust chamber '48 having an exhaust .port 49. The inlet chamber is'connected with the outlet chamber by means'of abore 5Il, whilethe-ou'tlet chamber isconnected withthe exhaust chamber by means of a 'bore "5i, preferably having the same area asthe'borefiil. Aspherical'inlet valve -52iPI0VldEd at its upper'end with'aipiston 53 is slidably mounted in the casing andadapted on upward movement to close the lower end of the bore 50 against the pressure of fluid in the inlet chamberfithe'valve being normally-maintained in closed position 'by'mea'ns'of'a spring 54 interposed between the lower surfaae-of'the piston and the casing. The piston is slidably moun'ted in a bore 55, preferably having the same diameter-as the bore 5U, and the inlet-chamber is provided with aninlet port 56 connected with supply reservoir 4 by mean'sof a conduit 1. The outlet chamber is rovided with an outlet'port-B'I-connected with {a pair of fluid actuatofs B by means-of conduits 9' an'd 'I U. The flow of fluid pressure through the bore 5l between the outlet *and exhaust cham- -b'ers"-is controlled-by means of '-a' spherical exhaust valve 58 provided with a stem 59, "and the exhaust valve is normally maintaine'd in the open p'osition shown by means of a spring tll interp'osed b'etwen the-easingand a flange "6| formed on the exhaust valve stem, if thus-being apparent that eloslngofthe exhaust valve must be effected gainst-the pressure of fiuid in theoutletcham. r.

{A cover member 62 is provided with a bracket '63havin'g an operating pedal '36 pivotally mounted thereon and adapted to engagea-plunger 31 slidably mounted in the casing. A-graduating'sprlng 4I,-of-a type 'similarto that shown in Fig. 1, is interposed between the plunger Slandthe center of a valve operating 'beam fi i in'the outlet chamber. A cover plate fi'5 for-'thebore55 is'attache'd to the"easing in the exhaust chamber as shown and provided with a central b'cre 66 adapted to slidably receive an inlet valve operating plunger 61, the lower end of the plunger engaging the upper end of the piston 53, and the upper end engaging a depression 68 formed on the lower surface of the beam 64. The left end of the beam is provided with a similar depression 69 and engages the upper end of the exhaust valve stem 59. The graduating spring 4| and the exhaust valve spring 60 are so proportioned that with the operating pedal and the inlet valve in the position shown, the exhaust valve is maintained normally in open position. Thus the flow of fluid pressure from the inlet chamber to the outlet chamber is prevented, and the outlet chamber is connected with atmosphere through the port 5|, the exhaust chamber 48 and the exhaust port 49.

In the event the operator desires to operate the valve mechanism to supply fluid pressure to the actuators 8, the pedal 36 is depressed, thus causing the plunger 31 to compress the graduating spring. The springs 54 and 60 are so chosen as to permit closing of the exhaust valve before the force exerted on the plunger 61 is sufiicient to move the inlet valve to open position, it being noted that the fluid pressure forces acting on the inlet valve in closed position are balanced due to the fact that the bores 50 and 55 have equal areas. Thus, the beam li l will pivot about the upper end of the plunger 6! during closing of the exhaust valve, and as the graduating spring is further compressed, the beam will pivot about the upper end of the exhaust valve stem 59 and move the plunger Bl downward to open the inlet valve, thus admitting fluid pressure from the inlet chamber to the outlet chamber and thence to the actuator through conduits 9 and I0. Assuming that the graduating spring is compressed a predetermined amount, the pressure in the outlet chamber will increase, and the upward force exerted on the exhaust valve due to this pressure will correspondingly increase. At the same time, the pressure differential across the valve 52 will decrease, and a condition will be reached wherein the force exerted downward on the inlet valve due to the flow of fluid through the bore 50 to the outlet chamber will be insufficient to maintain the valve in closed position against the force exerted by the inlet valve spring 54, whereupon the inlet valve will be moved to closed position, at the same time rocking the beam 64 about the upper end of the stem 59 in order to slightly compress the graduating spring. If the force exerted on the pedal is now reduced, the pressure in the outlet chamber will move the exhaust valve to open position to correspondingly reduce the outlet chamber pressure, and at the same time to rock the beam about the upper end of the plunger 61 to slightly compress the graduating spring. As the pressure decreases in the outlet chamber, the force exerted by th graduating spring will again be suflicient to move the exhaust valve back to closed position against the force exerted by the spring 60 and by the pressure of fluid in the outlet chamber, and both valves will then be closed in order to maintain a pressure in the outlet chamber substantially proportional to the force exerted on the graduating spring 4| by the operation of the operating pedal. With the valves in closed position, and a predetermined pressure established in the outlet chamber, it will be understood that any increase in pressure in the chamber due to leakage of the inlet valve will force the exhaust valve away from the upper end of the bore Si in '6 order to release the excess pressure to atmosphere through the exhaust chamber 48 and the exhaust port 49.

As heretofore stated, the inlet valve is balanced insofar as the forces exerted by the fluid pressure in the inlet chamber are concerned, and consequently the force required to move the valve to open position under all conditions of operation is relatively small, and the valve mechanism can be operated with a minimum of effort by the operator. The beam 64 insures sequential operation of the inlet and exhaust valves, and in the event the springs 54 and 60 are properly chosen,

prevents the possibility of both valves being open at the same time, a condition which would result in excessive and continuous leakage of fluid pressure from the valve mechanism through the exhaust port 49. As in the case of the structure shown in Fig. 1, the inlet valve is balanced insofar as the forces exerted by the pressure of fluid in the inlet chamber are concerned, and both valves are positioned to close against the pressure rather than with the pressure, thus resulting in a construction wherein the operating forces on the pedal are relatively small. At the same time, the pressure in the outlet chamber is at all times substantially proportional to the degree of movement of the pedal from released position, as well as to the degree of force exerted on the pedal by the operator, and the dimensions of the Various parts including the inlet and exhaust valve springs, can be so chosen as to insure an accurate and sensitive control of the degree of pressure supplied to the actuators. The valve operating element in Fig. 1, and the piston 53 in Fig. 2 are relatively small, and consequently the entire valve mechanism is extremely compact and of light weight, in view of the fact that relatively large pressure responsive members required in other types of self-lapping control Valves are unnecesary when the present type of construction is utilized.

While one embodiment of the invention and a modification thereof have been illustrated and described in considerable detail, it is to be understood that the invention is not limited thereto, but may be capable of being employed in other forms, as will be understood by those skilled in the art. Reference will, therefore, be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, out let and exhaust chambers, a spherical inlet valve for closing communication between the inlet and outlet chambers and mounted in the outlet chamber to open in the direction of flow of fluid from the inlet to the outlet chambers, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted in the exhaust chamber to be opened by pressure in the outlet chamber, a valve operating element connected with the inlet valve and having a part tending to close the inlet valve in opposition to the tendency of the inlet pressure to open the inlet valve, and means to operate said valves including means to move the element and inlet valve connected thereto.

2. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers, a valve operating element slidably mounted in a bore in said casing, said bore being of the same diameter throughout its length andhaving an inlet valve seat formed at one end and having. an intermediate portion connected with said inlet, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted in the exhaust chamber to be opened by pressure in the outlet chamber, a spherical inlet valve 'connected with said element and cooperating with said seat for closing communication between the inlet and outlet chambers and mounted in the outlet chamber to open in the direction of flow of fluid from the inlet to the outlet chambers, a spring for closing said inlet valve, and means to operate said valves including means to move the element and inlet valve connected thereto.

3. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers, a spherical inlet valve for closing communication between the inlet and'outlet chambers and mounted in the outlet chamber to open in the direction of flow of fluid from the inlet to the outlet chambers, a spherical. exhaust valve for closing communication between the outlet and exhaust chambers and mounted the exhaust chamber to be opened by pressure in the outlet chamber, a valve operating element 'connected with the inlet valve and slidably mounted in a bore in said casing, said bore being of the same diameter throughout its length, said element having a part tending to close the inlet valve in opposition to the tendency of the inlet pressure to open the inlet valve, a spring for closing said inlet valve, and means to operate said valves including means to move the element and inlet valve connected thereto.

4. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers together with a bore hav'- ing a pair of portions of equal diameter disposed on opposite sides of the inlet chamber and communicating therewith, a valve seat formed atone end of one of said portions, a valve operating element slidably mounted in the other portion, a spherical inlet valve connected with said element and cooperating with said seat to close communication between the inlet and outlet chambers and mounted in the outlet chamber to open in the direction of fluid flow, the effective areas of said element and said valve being equal so that the forces thereon are balanced when the valve is closed, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted in the exhaust chamber to be opened by pressure in the outlet chamber, and means to operate said valves including means to move the element and inlet valve connected thereto.

5. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers, a spherical inlet valve for closing communication between the inlet and outlet chambers and mounted to open in the direction of flow of fluid from the inlet to the outlet chambers, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to 'be opened by pressure in the outlet chamber, a valve operating element connected with the inlet valve andrhaving a part tending to close the inlet valve in opposition to the tendency of the inlet pressure to open the inlet valve, said element having a bore for connecting the outlet and exhaust chambers, and means to move the exhaust valve to close said bore and to then move the element to open the inlet valve.

6. In a self-lapping fluid. pressure valve mechanismhaving a casing provided with inlet, outlet and exhaust chambers, a valve operating element slidably mounted in a bore in said casing, said bore being of the same diameter throughout its length and having an inlet valve seat formed at one end, an intermediate portion connected with said inlet, and an exhaust passage for connecting the outlet and exhaust chambers, a spherical exhaust valve for closing said passage and mounted to be opened by pressure in the outlet chamber, a spherical inlet valve connected with said element and cooperating with said seat for closing communication between the inlet andoutlet chambers andv mounted to open in the direction of flow of fluid from the inlet to the outlet chambers, and means to move the exhaust valve to close said passage and to then move the element to: open the inlet'valve.

'7. In a self-lapping fluid pressure valve'me'chanism having a casing provided with inlet, outlet and exhaust chambers, a spherical inlet valvefor closing communication between the inlet and outlet chambers and mounted to open :in the direction of flow of fluid from the inlet to the outlet chambers, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to be opened by pressure in the outlet chamber, a valve operating element connected with the inlet valve and slidably mounted. in a bore in said. casing, said bore being or the same diameter throughout its. length and having a part tending to close the inlet valve in opposition to the tendency of the inlet pressure to open the inlet valve, said bore being also provided with an exhaust passage .for connecting the outlet and exhaust chambers, a spring tending to close the inlet valve, and: means to move the exhaust valve to close said passage and to then move the element to open the inlet valve.

8. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers together with a bore having a pair of portions of equal diameter disposed on opposite sides of the inlet chamber and :com- .municating therewith, a valve seatiormed at one end of one of said portions, a valve operating element slidably mounted in the other portion, and provided with an exhaust passage for connecting the outlet and exhaust chambers, a spherical in- .letvalve connected with said element and cooperating with said seat to close communication between the inlet and outlet chambers and mounted to open in the direction of fluid flow, the effective areas of said element and said valve being equal so that the forces thereon are balanced when the valve is closed, a spherical exhaust valve for closing communication between the outlet and exhaust chambers through said passage and mounted to be opened by pressure in the outlet chamber, and means to move the exhaust valve 'to close said passage and to then move the element to open the inlet valve.

9?. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers, a spherical inlet valve for'closing communication between the inlet and outlet chambers and mounted to open in the direction of flow of fluid from the inlet so the outlet chamber, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to be opened by pressure in the outlet chamber, a valve operating element connected with the inlet valve and having a part tending to close the inlet valve in opposition to the tendency of the inlet pressure to open the inlet valve, and means to operate said valves including a rocking beam for first closing the exhaust valve and then moving the element and inlet valve connected thereto to open the inlet valve.

10. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers, a valve operating element slidably mounted in a bore in said casing, said bore being of the same diameter throughout its length and having an inlet valve seat formed at one end and having an intermediate portion connected with said inlet, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to be opened by pressure in the outlet chamber, a spherical inlet valve connected with said element and operating with said seat for closing communication between the inlet and outlet chambers and mounted to open in the direction of flow of fluid from the inlet to the outlet chambers, a spring for closing said inlet valve, and means to operate said valves including a rocking beam for first closing the exhaust valve and then moving the element and inlet valve connected thereto to open the inlet valve.

11. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers, a spherical inlet valve for closing communication between the inlet and outlet chambers and mounted to open in the direction of fiow of fluid from the inlet to the outlet chambers, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to be opened by pressure in the outlet chamber, a valve operating element connected with the inlet valve and slidably mounted in a bore in said casing, said bore being of the same diameter throughout its length and having a part tending to close the inlet valve in opposition to the tendency of the inlet pressure to open the inlet valve, a spring for closing said inlet valve, and means to operate said valves including a rocking beam for first closing the exhaust valve and then moving the element and inlet valve connected thereto to open the inlet valve.

12. In a self-lapping fluid pressure valve mechanism having a casing provided with inlet, outlet and exhaust chambers together with a bore having a pair of portions of equal diameter disposed on opposite sides of the inlet chamber and communicating therewith, a valve seat formed at one end of one of said portions, a valve operating element slidably mounted in the other portion, a spherical inlet valve connected with said element and cooperating with said seat to close communication between the inlet and outlet chambers and mounted to open in the direction of fluid fiow, the effective areas of said element and said valve being equal so that the forces thereon are balanced when the valve is closed, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to be opened by pressure in the outlet chamber, and means to operate said valves including a rockin beam for first closing the exhaust valve and then moving the element and inlet valve connected thereto to open the inlet valve.

13. In a self-lapping fluid pressure valve mech anism having a casing provided with inlet, outlet and exhaust chambers together with a bore having a pair of portions of equal diameter disposed on opposite sides of the inlet chamber and communicating therewith, a valve seat formed at one end of one of said portions, a valve operating element slidably mounted in the other portion, a spherical inlet valve connected with said element and cooperating with said seat to close communication between the inlet and outlet chambers and mounted to open in the direction of fluid flow, the effective areas of said element and said valve being equal so that the forces thereon are balanced when the valve is closed, a spherical exhaust valve for closing communication between the outlet and exhaust chambers and mounted to be opened by pressure in the outlet chamber, a spring normally maintaining the exhaust valve open, a second spring normally maintaining the inlet valve closed, and means to operate said valves including a rocking beam for first closing the exhaust valve and then moving the element and inlet valve connected thereto to open the inlet valve.

ROGER H. CASLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 721,499 Brennan Feb. 24, 1903 1,526,452 Alder Feb. 17, 1925 1,707,742 Schjolin Apr. 2, 1929 79 2,040,590 Avery May 12, 1936 2,204,530 Eaton June 11, 1940 2,402,317 Du Bois Jan. 18, 1946 FOREIGN PATENTS Number Country Date 408,011 Great Britain Apr. 5, 1934 

